(Optional) Configuring the PHP Feature

Procedure

1. Run system-view

   The system view is displayed.

2. Run mpls

   The MPLS view is displayed.

3. Run label advertise { explicit-null | implicit-null | non-null }

   A label assigned to the penultimate node is specified.

   You can specify one of the following parameters:

   • explicit-null: disables PHP. If this parameter is configured, the egress assigns an explicit null label with value 0 to the penultimate node. explicit-null supports MPLS QoS, which helps save label resources in the egress. If E2E services with QoS attributes carried in the EXP field in a label are transmitted, explicit-null can be configured to save label resources and prevent EXP value loss.

   • non-null: disables PHP. If this parameter is configured, the egress assigns a label with a value greater than or equal to 16 to the penultimate node. The non-null label consumes resources on the egress, which is not recommended. This parameter can be used when the egress needs to identify services based on labels.

   

   After the label advertise { explicit-null | implicit-null | non-null } command is run to change the label distribution mode on the egress, the modification takes effect on new LSPs but not on existing LSPs. To enable the modification to take effect on the existing LSPs, run the reset mpls ldp or lsp trigger command.

4. Run commit

   The configurations are committed.